I also have a '54, someone replaced the bed and pump w/ a flatbed and U-joint hangar, 503 w/ 5 speed synchro, need PTO for box, drove home to Denver area from Al, brakes take 4 pumps to work may need hydrovac? Repair. 503 works fine, 6 to 9 MPG on way home, 6.5 rear ratio, needs 4.8 or so.

Made up electronic ignition so far, not installed yet, Deve's mod. Thinking about fuel injection in the future, want to keep gasser.

Ed

Last edited by EdPruss; 11/26/2015 11:28 PM.
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.